【Abstract】 Objective The present study employed both static and dynamic imaging modal ities to study bothintra- and extravascular events attributing to steroid-associated osteonecrosis (ON) using an experimental protocol with a single low-dose l i ppolysaccharide (LPS) injection and subsequently three injections of high-dose methylprednisolone (MPS). Methods Fourteen 28-week-old male New Zealand white rabbits received one intravenous injection of LPS (10 μg/ kg). After 24 hours, three injections of 20 mg/kg of MPS were given intramuscularly at a time interval of 24 hours. Additional 6 rabbits were used as controls. Dynamic MRI was performed on bilateral femora for local intraosseous perfusion before and after LPS injection. Blood samples were collected for haematological examinations before and after LPS injection. Bilateral femora were dissected and decalcified for microCT-based microangiography. ON lesion, intravascular thrombus and extravascular marrow fat cell size were examined histopathologically. Results Intravascular thrombus was observed in all ON rabbits. Extravascular marrow fat cell size was significantly increased in ON rabbits than that of the controls (P lt; 0.05). Compared to basel ine, a significant decrease in ratio of tissue-type-plasminogen-activator/plasminogen-activator inhibitor 1,activated-partial- thromboplatin-time, and a significant increase in ratio of low-density-l ipoprotein/high-density-l ipoprotein were only found in ON rabbits (P lt; 0.05). Dynamic MRI showed a significant decrease in the perfusion index ‘maximum enhancement’ in the ON rabbits (P lt; 0.05) and microCT-based microangiography showed blocked stem vessels in ON samples.Overall, 93% of the rabbits (13/14) developed ON and no rabbits died throughout the experiment period. Conclusion Bothintra- and extravascular events were found attributing to the steroid- associated ON based on our experimental protocol with a single low-dose LPS injection and subsequent three injections of high-dose MPS. Both high ON incidence and no mortal ity in rabbits treated with this inductive protocol suggested its effectiveness for future studies on evaluation of therapeutic efficacy of interventions developed for prevention of steroid-associated ON.
With high morbidity, branch retinal vein occlusion (BRVO) is a common retinal vascular disease in the clinic. Although the classic characteristics of BRVO have been recognized for a long time, the traditional understanding of BRVO has been challenged along with development and application of new imaging technologies, including the reasonable classification and staging of the disease, and the vascular characteristics at the occlusive site via multimodal imaging, etc. Thus, re-summarizing and refining these features as well as further improving and optimizing traditional imaging evaluation, can not only deepen the correct acknowledge of the entity, but also find biomarkers of prognosis of visual function, which is helpful to establish better diagnosis and treatment strategy. In the meanwhile, it is necessary that clinical characteristics of BRVO on imaging and the reliability of these imaging techniques are worth correct understanding and objective assessment.
Objective
To evaluate the possible role of vascular endothelial growth factor (VEGF) in the pathogenesis of retinal neovascularization resulting from retinal ischemia．
Methods
Retinal vein occlusion of rabbits model was established with argon laser photo coagulation to retinal vein．The VEGF mRNA expression was observed in ischemic retina and retinal neovascular tissue with in situ hybridization technique．
Results
VEGF mRNA expression was detected in inner ischemic retina and retinal neovascular tissue that were corespondent to the distribution of retinal ischemia．The best VEGF mRNA expression was detected in retinal neovascular tissue．
Conclusion
VEGF might play an important role in the pathogenesis of vascular proliferative retinopathy．
(Chin J Ocul Fundus Dis, 2001,17:5-7)
Objective To observe the preventive and therapeutic effect of different times, spot reactions and spot density of argon laser photocoagulation on retinal neovas cularization of ischemic retinal vein occlusion (IRVO).Meth9al of 244 patients (268 eyes) with IRVO diagnosed by fundus fluorescein angiography (FFA) were treated by HGM argon laser photocoagulator with green-blue light with 200~500 μm lightspot, 0.1~0.5 s, 0.3~1.0 w, and II~III class spot reaction . All capillary nonperfusion areas (CNA) were photocoagulated, and so were the retinal neovascularization in some patients. The follow up periods were from 6 to 60 months. After 3 and 24 weeks after photocoagulation FFA was performed again. Photocoagulation was performed supplementarilly for the new CNA or incompletely photocoagulated areas. Ophthalmoscopic examination and FFA were performed in all the patients after half a year.Results Only 17 eyes (10.6%) with neovascularization were found after preventive photocoagulation in 160 eyes in non-neovacularization group. Sixty-nine eyes(63.9%) with neovascular atrophy and 39 eyes (36 .1%) with unsuccessful photocoagulation were found after therapeutic photocoagulation in 108 eyes in neovascularization group. There was statistical significance between the two groups (P＜0.01). Photocoagulation energy with reaction of III class and density of 1 lightspot diameter was more effective than which with reaction of II~III class and density of 1.5 lightspot diameter or reaction of ≤II class and density of 2 lightspot diameter (P＜0.01). Conclusion Efficacy of preventive photocoagulation is better than which of therapeutic photocoagulation. Photocoagulation energy with reaction of III class and density of 1 lightspot diameter is an effective method for IRVO.(Chin J Ocul Fundus Dis，2003，19：201-268)
Objective
To observe the difference of macular microvascular features in superficial and deep vascular plexi in patients with branch retinal vein occlusion (BRVO).
Methods
A total of 63 BRVO patients (63 eyes) were enrolled in this study. There were 28 males (28 eyes) and 35 females (35 eyes). The patients aged from 39 to 74 years, with the mean age of (59.76±8.48) years. All eyes were evaluated by optical coherence tomography angiography (OCTA). The macular angiography scan protocol covered a 3 mm×3 mm area. The focus of angiography analysis included superficial vascular plexus and deep vascular plexus. The following vascular morphological parameters were assessed in these two plexi: foveal avascular zone (FAZ) enlargement, capillary non-perfusion (CNP) occurrence, microvascular abnormalities (MA) appearance, and vascular congestion (VC) signs. The FAZ area was measured by the built-in software. The macular microvascular morphology changes in superficial and deep vascular plexi were compared through McNemar test.
Results
The superficial and deep plexi showed FAZ enlargement in 43 eyes (68.3%) and 50 eyes (79.4%), CNP in 51 eyes (81%) and 50 eyes (79.4%), MA in 62 eyes (98.4%) and 62 eyes (98.4%), VC in 23 eyes (36.5%) and 52 eyes (82.5%), respectively. FAZ area was (0.55±0.37) mm2. There was no difference in CNP (P=1.000) and MA (P=1.000) between superficial and deep plexi. But, there was difference in FAZ enlargement (P=0.039) and VC signs (P＜0.001) between superficial and deep plexi.
Conclusion
Deep vascular plexus showed more FAZ enlargement and VC sign than superficial plexus in BRVO patients.
ObjectiveTo study a deep learning-based dual-modality fundus camera which was used to study retinal blood oxygen saturation and vascular morphology changes in eyes with branch retinal vein occlusion (BRVO). MethodsA prospective study. From May to October 2020, 31 patients (31 eyes) of BRVO (BRVO group) and 20 healthy volunteers (20 eyes) with matched gender and age (control group) were included in the study. Among 31 patients (31 eyes) in BRVO group, 20 patients (20 eyes) received one intravitreal injection of anti-vascular endothelial growth factor drugs before, and 11 patients (11 eyes) did not receive any treatment. They were divided into treatment group and untreated group accordingly. Retinal images were collected with a dual-modality fundus camera; arterial and vein segments were segmented in the macular region of interest (MROI) using deep learning; the optical density ratio was used to calculate retinal blood oxygen saturation (SO2) on the affected and non-involved sides of the eyes in the control group and patients in the BRVO group, and calculated the diameter, curvature, fractal dimension and density of arteriovenous in MROI. Quantitative data were compared between groups using one-way analysis of variance. ResultsThere was a statistically significant difference in arterial SO2 (SO2-A) in the MROI between the affected eyes, the fellow eyes in the BRVO group and the control group (F=4.925, P<0.001), but there was no difference in the venous SO2 (SO2-V) (F=0.607, P=0.178). Compared with the control group, the SO2-A in the MROI of the affected side and the non-involved side of the untreated group was increased, and the difference was statistically significant (F=4.925, P=0.012); there was no significant difference in SO2-V (F=0.607, P=0.550). There was no significant difference in SO2-A and SO2-V in the MROI between the affected side, the non-involved side in the treatment group and the control group (F=0.159, 1.701; P=0.854, 0.197). There was no significant difference in SO2-A and SO2-V in MROI between the affected side of the treatment group, the untreated group and the control group (F=2.553, 0.265; P=0.088, 0.546). The ophthalmic artery diameter, arterial curvature, arterial fractal dimension, vein fractal dimension, arterial density, and vein density were compared in the untreated group, the treatment group, and the control group, and the differences were statistically significant (F=3.527, 3.322, 7.251, 26.128, 4.782, 5.612; P=0.047, 0.044, 0.002, <0.001, 0.013, 0.006); there was no significant difference in vein diameter and vein curvature (F=2.132, 1.199; P=0.143, 0.321). ConclusionArterial SO2 in BRVO patients is higher than that in healthy eyes, it decreases after anti-anti-vascular endothelial growth factor drugs treatment, SO2-V is unchanged.
In order to summarize the experience in the treatment of ischemic necrosis of lower extremities resulted from thrombotic occluded angittis, 15 cases were reported, which were treated by primary arterization in situ of V. Saphena magna. With a period of follow-up, 4-26 months on the average, it was found that symptoms in 14 cases were much allayed obviously, except 1 case with little relief. It suggested that primary arterization in situ of V. saphena magna could improve the circulation of the ischemic extremity rapidly without any influence of venous reflux.
Objective To observe the changes of photopic negative response (PhNR) of electroretinography (ERG) in patients with retinal vein occlusion (RVO). Methods A total of 30 patients (30 eyes) with retinal vein occlusion (RVO) diagnosed by indirect ophthalmoscopy and fundus fluorescein angiography (FFA) were selected; the unaffected fellow eyes of the patients and another 25 healthy agematched individuals (50 eyes) were cllected as the normal control. All of the patients underwent the examination of visual acuity, visual field, and flashERG (FERG); the normal control ones underwent FERG. In the 30 patients with RVO, there were 14 with central RVO (CRVO) and 16 with branch RVO (BRVO). According to the disease history and results of FFA, the patients were divided into 3 time groups: lt;1 month, 1-3 months, and gt;3 months; according to the types of RVO, the patients were divided into ischemic and nonischemic group. The amplitude of PhNR and other parameters were analysed. The relationship among the amplitude of PhNR and RVO types and time course were analyzed.Results The amplitude of PhNR in the CRVO and BRVO eyes was (28.20plusmn;5.8) and (36.96plusmn;4.71) mu;V, respectively; those in the unaffected fellow and control eyes was (61.25plusmn;3.93) and (59.33plusmn;16.92) mu;V, respectively; the amplitude of PhNR was significantly smaller in the CRVO and BRVO eyes than those in the unaffected fellow or control eyes (F=10.69 and 9.80，P＜0.001; F=9.69 and 9.75，P＜0.001). The amplitude of PhNR in ischemic and nonischemic group in CRVO eyes was (22.77plusmn;15.73) and (36.63plusmn;12.91) mu;V, respectively; the difference between the two groups was significant（t=6.54, Plt;0.01）. The amplitude of PhNR in ischemic and nonischemic group in BRVO eyes was (32.39plusmn;13.22) and (46.73plusmn;10.43) mu;V, respectively; there was no significant difference between the two groups（t=2.12, Plt;0.05）. The amplitude of PhNR was (24.58plusmn;14.60) and (27.94plusmn;15.73) mu;V, respectively, in CRVO and BRVO eyes with lt; 1 month disease course; was (50.39plusmn;13.80) and (58.69plusmn;12.43) mu;V in those with 1-3 months disease course; and was (25.40plusmn;19.94) and (34.48plusmn;16.72) mu;V in those with ＞3 months diseases course. Significant difference was found between the 1-3 months group and ＞3 months group in CRVO eyes（F=4.30，Plt;0.01）. Conclusions The amplitude of PhNRs was significantly smaller in RVO eyes than those in the unaffected fellow or control eyes.The amplitude of PhNR amplitude of ischemic type was smaller than that of nonischemic type. The amplitude of PhNR has descending，ascending，and descending tendency during the disease courses.
Purpose
To evaluate the significance of axial length in case of branch retinal vein occlusion(BRVO).
Methods
A case-control study of axial length was performed using 34 patients with BRVO and 34 age and sex-matched control patients selected from a list of subjects who had undergone cataract extraction.Axial length measurement were taken with an A-scan ultrasonography.
Results
The affected and fellow eye in patinets of BRVO group did not differ statistically in axial length (P＞0.20).The mean axial length of affected eyes in BRVO group was （23.16plusmn;0.82）mm, and the mean axial length of control eyes was（23.78plusmn;1.06）mm.The difference in axial length between the eyes with BRVO and the eyes in the control group was not statistically significant(P＞0.10).
Conclusion
Hyperopia as measured by axial length is not a risk factor to BRVO.
(Chin J Ocul Fundus Dis,1998,14:12-13)
